Donepezil hydrochloride of formula (1):
or 2,3-Dihydro-5,6-dimethoxy-2-[[1-(phenylmethyl)-4-piperidinyl]methyl]-1H-inden-1-one hydrochloride is useful for prevention and treatment of alzheimer disease. The therapeutic uses of donepezil hydrochloride and related compounds are disclosed in EP 296560.
U.S. Pat. No. 6,140,321 disclosed four crystalline forms of donepezil hydrochloride, polymorph (I), polymorph (II), polymorph (III) and polymorph (IV) and processes for preparation thereof.
It has now been discovered that donepezil hydrochloride can be prepared in four stable crystalline forms having good dissolution characteristics.
The object of the present invention is to provide stable novel crystalline forms of donepezil hydrochloride, processes for preparing these forms and pharmaceutical compositions containing them.